The present invention relates to a sheet folding method for folding the sheet, sheet folding apparatus, and sheet finisher by which the sheet on which an image is formed is folded after the image formation, and image forming apparatus.
In Japanese Tokkaihei No. 10-194586, or Tokkai No. 2002-060127, as the sheet folding apparatus, the apparatus by which the folding is conducted by using a knife-like folding member, or an apparatus by which, by pressing the sheet leading edge to the stopper and conveying the sheet, the sheet is bent and folded, is proposed.
In the former folding apparatus, the apparatus becomes large because the knife-like folding member is reciprocally moved, and there is a problem when it is used for the sheet finisher used as an auxiliary device of the image forming apparatus, and in the latter folding apparatus, there is a problem that it is difficult to fold the sheet at the accurate position.
An object of the present invention is to solve the above problem in the conventional sheet folding apparatus.
The object of the present invention is attained by any one of the following Structures (1) to (20).
(1) A sheet folding method which is characterized in that: it has the first introduction process to introduce a sheet between the first rotary folding body and the first rotary pressure-contact body, and between the second rotary folding body and the second rotary pressure-contact body, by using the first conveying means composed of the first rotary folding body and the first rotary pressure-contact body and the second conveying means which is composed of the second rotary folding body and the second rotary pressure-contact body and arranged upstream of the first conveying means; the first folding process in which, under the condition that the first rotary folding body is in contact with the first rotary pressure-contact body, the second rotary folding body is in contact with the second rotary pressure-contact body, and the first rotary folding body is in contact with the second rotary folding body, when the first and second rotary folding bodies are rotated in the reversal direction to each other, the conveying force of reversal directions to each other is acted by the first conveying means and the second conveying means and the sheet is bent and a fold is formed, and the fold of the sheet is conveyed between the first rotary folding body and the second rotary folding body and the sheet is folded; the second introduction process to introduce the sheet folded by the first folding process between the third rotary folding body and the third rotary pressure-contact body, and between the fourth rotary folding body and the fourth rotary pressure-contact body, by using the third conveying means composed of the third rotary folding body and the third rotary pressure-contact body, and the fourth conveying means which is composed of the fourth rotary folding body and the fourth rotary pressure-contact body and arranged upstream the third conveying means; and the second folding process in which, under the condition that the third rotary folding body is in contact with the third rotary pressure-contact body, the fourth rotary folding body is in contact with the fourth rotary pressure-contact body, and the third rotary folding body is in contact with the fourth rotary folding body, when the third and fourth rotary folding bodies are rotated in the reversal direction to each other, the conveying force of reversal directions to each other is acted by the third conveying means and the fourth conveying means and the sheet is bent and a fold is formed, and the fold of the sheet is conveyed between the third rotary folding body and the fourth rotary folding body and the sheet is folded.
(2) A sheet folding method according to Structure (1), wherein, in the first introduction process, the first rotary pressure-contact body is brought into contact with the first rotary folding body, and the second rotary folding body and the second rotary pressure-contact body are separated from each other, and the sheet is conveyed and introduced by the first conveying means.
(3) A sheet folding method according to Structure (1), wherein, in the first introduction process, the second rotary pressure-contact body is brought into contact with the second rotary folding body, and the first rotary folding body and the first rotary pressure-contact body are separated from each other, and the sheet is conveyed and introduced by the second conveying means.
(4) A sheet folding method according to Structure (1), wherein, in the second introduction process, the third rotary pressure-contact body is brought into contact with the third rotary folding body, and the fourth rotary folding body and the fourth rotary pressure-contact body are separated from each other, and the sheet is conveyed and introduced by the third conveying means.
(5) A sheet folding method according to Structure (1), wherein, in the second introduction process, the fourth rotary pressure-contact body is brought into contact with the fourth rotary folding body, and the third rotary folding body and the third rotary pressure-contact body are separated from each other, and the sheet is conveyed and introduced by the fourth conveying means.
(6) A sheet folding method according to Structure (1), wherein, in the first introduction process, the first rotary pressure-contact body is brought into contact with the first rotary folding body, and the second rotary folding body is separated from the first rotary folding body and the second rotary pressure-contact body from each other, and by driving the first rotary folding body, the sheet is conveyed and introduced by the first conveying means.
(7) A sheet folding method according to Structure (1), wherein, in the first introduction process, the second rotary pressure-contact body is brought into contact with the second rotary folding body, and the first rotary folding body is separated from the second rotary folding body and the first rotary pressure-contact body from each other, and by driving the second rotary folding body, the sheet is conveyed and introduced by the second conveying means.
(8) A sheet folding method according to Structure (1), wherein, in the second introduction process, the third rotary folding body is brought into contact with the third rotary pressure-contact body, and the fourth rotary folding body is separated from the third rotary folding body and the fourth rotary pressure-contact body from each other, and by driving the third rotary folding body, the sheet is conveyed and introduced by the third conveying means.
(9) A sheet folding method according to Structure (1), wherein, in the second introduction process, the fourth rotary folding body is brought into contact with the fourth rotary pressure-contact body, and the third rotary folding body is separated from the fourth rotary folding body and the third rotary pressure-contact body from each other, and by driving the forth rotary folding body, the sheet is conveyed and introduced by the fourth conveying means.
(10) A sheet folding method according to Structure (1), wherein, in the first introduction process, under the condition that the first rotary pressure-contact body is separated from the first rotary folding body, and the second rotary pressure-contact body is separated from the second rotary folding body, the sheet is introduced by the introduction means.
(11) A sheet folding method according to Structure (1), wherein, in the second introduction process, under the condition that the third rotary pressure-contact body is separated from the third rotary folding body, and the fourth rotary pressure-contact body is separated from the fourth rotary folding body, the sheet is introduced by the introduction means.
(12) A sheet folding method according to Structure (1), wherein, in the first introduction process, the first rotary folding body and the second rotary folding body are separated from each other, and under the condition that the first rotary pressure-contact body is brought into contact with the first rotary folding body, and the second rotary pressure-contact body is brought into contact with the second rotary folding body, when the first and second folding rotation bodies are rotated in the same direction, the sheet is introduced.
(13) A sheet folding method according to Structure (12), wherein, in the first folding process, either one of the first or the second rotary folding body is driven by the drive means, and the other one is driven.
(14) A sheet folding method according to Structure (1), wherein, in the second introduction process, the third rotary folding body and the fourth rotary folding body are separated from each other, and under the condition that the third rotary pressure-contact body is brought into contact with the third rotary folding body, and the fourth rotary pressure-contact body is brought into contact with the fourth rotary folding body, when the third and fourth rotary folding bodies are rotated in the same direction, the sheet is introduced.
(15) A sheet folding method according to Structure (14), wherein, in the first folding process, either one of the third or the fourth rotary folding body is driven by the drive means, and the other one is driven.
(16) A sheet folding method according to Structures (1) to (15), wherein, in the first and the second folding processes, by the first guiding means arranged between the first conveying means and the second conveying means, and the second guiding means arranged between the third conveying means and the fourth conveying means, the sheet is guided so that it bends toward one direction.
(17) A sheet folding apparatus which has: the first conveying means composed of the first rotary folding body and the first rotary pressure-contact body; the second conveying means which is composed of the second rotary folding body and the second rotary pressure-contact body and arranged upstream of the first conveying means; the first folding section having the first displacement means and the first drive means which drives at least one of the first rotary folding body and the second rotary folding body; and the second folding section having the third conveying means composed of the third rotary folding body and the third rotary pressure-contact body, the fourth conveying means which is composed of the fourth rotary folding body and the fourth rotary pressure-contact body and arranged upstream of the third conveying means, the second displacement means and the second drive means which drives at least one of the third rotary folding body and the fourth rotary folding body, the sheet folding apparatus is characterized in that the first folding section folds the sheet at a first position thereof by one of the following operations A, B, C, and D; and the second folding section folds the sheet at a second position different from the first position by one of the following operations E, F, G and H,
where the operation A represents that the first rotary pressure-contact body is brought into contact with the first rotary folding body, the second rotary folding body is brought into contact with the first rotary folding body, the first driving device drives the first rotary folding body in a condition that the second rotary pressure-contact body is separated from the second rotary folding body, thereby the sheet is conveyed and introduced to the first folding section by the first rotary folding body and the first pressure-contact body, then the first displacement device brings the first rotary pressure-contact body and the second rotary pressure-contact body into contact with the first folding body and the second folding body, respectively, and the first driving device drives the first rotary folding body and the second rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the first and second rotary folding bodies;
the operation B represents that the first rotary pressure-contact body is brought into contact with the first rotary folding body, the first driving device drives the first rotary folding body in a condition that the second rotary folding body is separated from the first rotary folding body and the second rotary pressure-contact body, thereby the sheet is conveyed and introduced to the first folding section by the first rotary folding body and the first pressure-contact body, then the first displacement device brings the second rotary folding body into contact with the first rotary folding body and the second rotary pressure-contact body, and the first driving device drives the first rotary folding body and the second rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the first and second rotary folding bodies;
the operation C represents that the first rotary pressure-contact body and the second rotary pressure-contact body are brought into contact with the first rotary folding body and the second rotary folding body, respectively, the first driving device drives the first rotary folding body and the second rotary folding body so as to be rotated in the same direction in a condition that the first rotary folding body is separated from the second rotary folding body, the first displacement device brings the first rotary folding body into contact with the second rotary folding body, and the first driving device drives the first rotary folding body and the second rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the first and second rotary folding bodies;
the operation D represents that the first driving device drives the sheet in conditions that the first rotary pressure-contact body and the second rotary pressure-contact body are separated from the first rotary folding body and the second rotary folding body, respectively, the first displacement device brings the first rotary pressure-contact body and the second rotary pressure-contact body into contact with the first rotary folding body and the second rotary folding body, respectively, and the first driving device drives the first rotary folding body and the second rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the first and second rotary folding bodies,
the operation E represents that the third rotary pressure-contact body is brought into contact with the third rotary folding body, the fourth rotary folding body is brought into contact with the third rotary folding body, the second driving device drives the third rotary folding body in a condition that the fourth rotary pressure-contact body is separated from the fourth rotary folding body, thereby the sheet folded by the first folding section is conveyed and introduced to the second folding section by the third rotary folding body and the first pressure-contact body, then the second displacement device brings the third rotary pressure-contact body and the fourth rotary pressure-contact body into contact with the third rotary folding body and the fourth rotary folding body, respectively, and the second driving device drives the third rotary folding body and the fourth rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the third and fourth rotary folding bodies;
the operation F represents that the third rotary pressure-contact body is brought into contact with the third rotary folding body, the second driving device drives the third rotary folding body in a condition that the fourth rotary folding body is separated from the third rotary folding body and the fourth rotary pressure-contact body, thereby the sheet is conveyed and introduced to the second folding section by the third rotary folding body and the first pressure-contact body, then the second displacement device brings the fourth rotary folding body into contact with the third rotary folding body and the fourth rotary pressure-contact body, and the second driving device drives the third rotary folding body and the fourth rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the third and fourth rotary folding bodies;
the operation G represents that the third rotary pressure-contact body and the fourth rotary pressure-contact body are brought into contact with the third rotary folding body and the fourth rotary folding body, respectively, the second driving device drives the third rotary folding body and the fourth rotary folding body so as to be rotated in the same direction in a condition that the third rotary folding body is separated from the fourth rotary folding body, the second displacement device brings the third rotary folding body into contact with the fourth rotary folding body, and the second driving device drives the third rotary folding body and the fourth rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the third and fourth rotary folding bodies; and
the operation H represents that the second driving device drives the sheet in conditions that the third rotary pressure-contact body and the fourth rotary pressure-contact body are separated from the third rotary folding body and the fourth rotary folding body, respectively, the second displacement device brings the third rotary pressure-contact body and the fourth rotary pressure-contact body into contact with the third rotary folding body and the fourth rotary folding body, respectively, and the second driving device drives the third rotary folding body and the fourth rotary folding body so as to be rotated in a direction opposite to each other, thereby conveyance force in an opposite direction is exerted on the sheet, the sheet is bent, a fold is formed on the sheet, and then the sheet is folded by making the fold to pass between the third and fourth rotary folding bodies.
(18) A sheet folding apparatus according to Structure (17), wherein the first folding section and the second folding section are arranged at a distance which is larger than half the maximum length of the sheet to be folded.
(19) A sheet finisher which is characterized in that it has the sheet folding apparatus according to Structure (17) or (18).
(20) An image forming apparatus which is characterized in that it has the sheet folding apparatus according to Structure (17) or (18).